The disclosures herein relate generally to detection of POST 80h codes in a personal computer and, more particularly, to a system and method for accessing such codes using a universal serial bus (xe2x80x9cUSBxe2x80x9d) or other port of a computer.
During the boot-up and power-on self-test (xe2x80x9cPOSTxe2x80x9d) sequence of a computer, many tasks are executed, each of which must be successfully completed before the computer may be used. Once the video system is initialized, the progress of the boot-up sequence can be communicated using error and other messages displayed on the display of the computer. Specifically, if the computer xe2x80x9changsxe2x80x9d prior to successful completion of the boot-up sequence, but subsequent to the initialization of the video system, an error message detailing the failure will be displayed, thereby facilitating the troubleshooting process.
Additionally, each POST task executed by a computer during boot-up thereof is assigned an 8-bit POST code that is written to I/O address 0080h (xe2x80x9cport 80hxe2x80x9d) prior to execution of the associated task. If the computer fails to boot-up properly prior to initialization of the video system, the last POST code issued can be examined to determine what task caused the computer to xe2x80x9changxe2x80x9d. One method of accessing the POST codes involves installation of a special expansion card, commonly referred to as a POST 80h card. Installation of a POST 80h card requires removal of the cover of the computer chassis and installing the card in one of the expansion slots provided within the chassis. Generally, installation and configuration of a POST 80h card is beyond the expertise of most computer users.
Other methods exist for diagnosing computer board-level problems, such as logic analyzers, in-circuit analyzers, oscilloscopes, and diagnostic LEDs. However, each of these methods is expensive and requires user-intervention to determine the cause of the problem.
Therefore, what is needed is an apparatus and a method for enabling POST 80h codes to be more easily accessed.
One embodiment, accordingly, provides an apparatus and method for accessing POST 80h codes, or data, using a USB port of a computer. To this end, a computer includes a processor connected to a memory device via one or more buses. During boot up of the computer, generated POST 80h codes, are accessed. This is accomplished by outputting the POST 80h codes via a serial port of the computer by connecting to the serial port for receiving the POST 80h codes.
A technical advantage achieved is that, because the USB-defined signaling protocol is not used, it is unnecessary for the USB port and USB controller to be up and running to output the POST 80h codes. As a result, POST 80h codes can be accessed without requiring a user to install an expansion card within the chassis of a computer. In addition, POST 80h codes are available almost instantaneously via the display of an external plug-in device.